The major effect of this proposal is to examine the influence of the catecholamines, dopamine and norepinephrine, as well as adrenergic drugs on water and electrolyte metabolism. The intrarenal pharmacologic and physiologic effects of dopamine will be correlated with alterations in renal blood flow, solute excretion and intratubular transport changes. Alterations in plasma and urinary dopamine conjugation and excretion following volume expansion will be measured. The influence of intrarenal alpha-adrenergic receptor subtypes on salt and water reabsorption will be examined pharmacologically. These studies will contribute to the understanding of catecholamines to the regulation of salt and water balance.